Hi,
It's not a first time when I experience problems with 'yum update' trying for a long time to connect to some very slow mirror. The only mirror that causes such problems for me is 'vilkam.ru', see the error below:
--- http://mirror.vilkam.ru/centos/7.2.1511/os/x86_64/repodata/c6411f1cc8a000ed2...: [Errno 14] curl#7 - "Failed connect to mirror.vilkam.ru:80; Connection refused" Trying other mirror. ---
Is there any way to notify admins of that mirror to improve its availability, or maybe remove it from the list of mirrors?